1. FIELD OF THE INVENTION
This invention relates to a transmission for use as the transmission system of a motorcycle, an automobile and the like, and more particularly to a transmission in which a V-belt type of stepless variable speed gear is provided between an input shaft linked to the output shaft of an engine and an output shaft linked to the driving wheel or wheels, so that the gear ratio between the input and output shafts can be controlled on a stepless basis.
2. DESCRIPTION OF THE PRIOR ART
The advantage of this V-belt type of stepless variable speed gear is an excellent drivability which is readily made available for a motor vehicle under various driving conditions, including starting, accelerating, deceleration, climbing, cruising and so on, by changing each of the effective radii of a driving V-pulley linked to the input shaft and a driven V-pulley linked to the output shaft, or the radii of them in contact with a V-belt. However, because of a certain degree of slip between the V-belt and the V-pulleys, its disadvantage is that transmission efficiency is inferior to that of an interlocking transmission gear employing gears and chains; this is also disadvantageous in view of fuel-saving.
In the meantime, since the length of time in which a motor vehicle is cruising is normally longer than that in which it is in other driving conditions, it is vertually unnecessary to change the gear ratio when cruising; in other words, the stepless speed-changing function of the V-belt stelpless variable speed gear is not required. Accordingly, it is preferred to adopt the interlocking transmission gear with its high transmission efficiency instead of the stepless variable speed gear.